Chemical Synthesis of a Heat-stable Enterotoxin Produced by Enterotoxigenic<i>Escherichia coli</i>Strain 18D
作者:Shoko Yoshimura、Makoto Miki、Haruo Ikemura、Saburo Aimoto、Yasutsugu Shimonishi、Tae Takeda、Yoshifumi Takeda、Toshio Miwatani
DOI:10.1246/bcsj.57.125
日期:1984.1
Two peptides with the two primary structures of 18 amino acid residues proposed for a heat-stable enterotoxin from enterotoxigenic Escherichia coli strain 18D were synthesized by solution methods and their physicochemical and biological properties were compared with those of native toxin. One of these peptides (Asn–Thr–Phe–Tyr–Cys–Cys–Glu–Leu–Cys–Cys–Asn–Pro–Ala–Cys–Ala–Gly–Cys–Tyr) showed the same heat-stability and 1H-NMR spectrum as those of the native toxin and evoked fluid secretion in suckling mice at a dose of 1.5–2.0 ng, which is similar to the effective dose of native toxin. Moreover, its toxicity was neutralized by antisera against the native toxin. The other peptide (Asn–Thr–Phe–Tyr–Cys–Cys–Glu–Leu–Cys–Cys–Tyr–Pro–Ala–Cys–Ala–Gly–Cys–Asn) showed different physicochemical and biological behaviors from those of the native toxin and exhibited toxic activity at a dose of 50–80 ng, which is about thirty times the effective dose of the native toxin. Moreover, its toxicity was not neutralized by antisera against the native toxin. These observations indicate that the former peptide is identical to native toxin but that the latter peptide differs in properties from the native toxin.
利用溶液法合成了产肠毒素大肠杆菌18D菌株中一种热稳定肠毒素所提出的两种由18个氨基酸残基组成的主要结构肽段,并将其理化性质和生物学性质与天然毒素进行了比较。其中一种肽段(天冬酰胺-苏氨酸-苯丙氨酸-酪氨酸-半胱氨酸-半胱氨酸-谷氨酸-亮氨酸-半胱氨酸-半胱氨酸-天冬酰胺-脯氨酸-丙氨酸-半胱氨酸-丙氨酸-甘氨酸-半胱氨酸-酪氨酸)与天然毒素表现出相同的热稳定性、1H-NMR 谱图,且在 1.5-2.0 ng 剂量下诱发乳鼠分泌液体,这与天然毒素的有效剂量相似。此外,该肽段的毒性可被针对天然毒素的抗血清中和。另一种肽段(天冬酰胺-苏氨酸-苯丙氨酸-酪氨酸-半胱氨酸-半胱氨酸-谷氨酸-亮氨酸-半胱氨酸-半胱氨酸-酪氨酸-脯氨酸-丙氨酸-半胱氨酸-丙氨酸-甘氨酸-半胱氨酸-天冬酰胺)与天然毒素表现出不同的理化性质和生物学行为,其毒性活动所需的剂量为50-80ng,约为天然毒素有效剂量的三十倍。此外,该肽段的毒性不能被针对天然毒素的抗血清中和。这些观察结果表明,前一种肽段与天然毒素相同,但后一种肽段在性质上与天然毒素不同。